I have a PB 17", 1.5 ghz. I just upgraded to Tiger, which worked fine. But, when I upgraded to 10.4.4. I was left with no sound. I tried reinstalling 10.4.4, but that did not fix the problem. I have double checked sound preferences, have tried ear phones, have tried different programs. I'm out of ideas .. Any suggestions? Or, anyone else have this problem?